Yellow flags used to be the calling card of Arizona State's defense. On any given Saturday in recent years it would litter the playing surface at Sun Devil Stadium at the most inopportune of times, costing wins, and ultimately, jobs.

Junior Onyeali knows he as much as anyone bears responsibility. The junior defensive end used to be known for his critical late hits and explosive mouth as much as his high-rev, sack-generating motor that led to Rivals.com Freshman All-American honors in 2010.

But now, Onyeali is the personification of Todd Graham's seed of change in Tempe, a seed that is not only growing, but taking root in the culture of ASU football.

"I was shocked," Onyeali said of the ASU defense being penalthy-free in last week's win over Northern Arizona. "In the game I was like, 'I don't think we've got a penalty.' I thought we might have had one but then after [coach Todd Graham] was like, 'We had zero penalties (on defense).' I was like, 'That is crazy.' Obviously since I've been here that hasn't happened and just to think we had no penalties, that's wild to think about.

"I think it the proof is in the pudding. As long as we're not getting penalties and as long as we're staying disciplined, people are going to say what coach Graham's teaching is right. I believe it's right and a lot of players have bought in and that's the reason we had zero penalties."

Graham not only preaches about the importance of discipline, but endeavors to have them understand excatly what it is. To that end, he recently had a Pac-12 officiating crew visit with his team to discuss what constitutes a penalty and how the game is seen and called for their perspective.

"What are they looking at on each snap?" Graham said of the things his players learned. "What is the referee looking at, what is the umpire looking at, how do they operate, how is the ball spotted? We don't want to give the ball to the official, we want to give the ball to the umpire, he's the one who spots it and it gets it spotted faster.

"So we talk to them about how do they determine a holding penalty, how do they determine a block in the back. So we bring them in and actually go into meetings and educate the players. I think just saying you don't want any penalties and doing it is completely different. I promise the whole game, I stand on the sideline and make them conscious, but I don't want them playing cautious."

The experience, Onyeali said, was beneficial.

"We had officials show us when they would call a holding, when they wouldn't, the different opinions, and just if we had something to talk about, which official to talk to," he said. "They just broke those things down. It was definitely helpful."

Penalties, just like the fumbles by senior running back Cameron Marshall and freshman running back D.J. Foster, will lead to a sprint to the sideline for some time to think about the mistake.

"I'd be right next to coach Graham," Onyeali said. "Even if it was the worst call possible I'd be sitting next to him for a player or two. He wouldn't yell at me but I'd just be on the sideline, that's it."

As Graham said this week, there will be bigger tests and greater adversity ahead, opportunities to back-slide to what has been the historical norm. But Onyeali believes the team is done with that and ready to see what's possible when the hallmark of the defense can be when it stops action at the whistle and is silent until the next play.

"We know we killed ourselves last year so the whole thing is, let's not kill ourselves this year," he said. "If we get beat, we want the opponent to beat us. We don't want to beat ourselves any more. We're tired of putting ourselves in horrible situations, we're tired of losing games just because we have to let it go down to a field goal when it could have been just a couple less penalties or, just more disciplined, playing our responsibilities, we just don't want it to happen any more.

"I don't even think I said one word to an official last week. Not hey, how are you doing? Just play and if he gives a bad call, just, 'Yes, sir.'"